Hello,

I have been looking into your question and what I can say is that currently, AppBuilder only supports endpoints returning array or object. Endpoints that are described to return primitive types (or are lacking description of the return type) are being greyed out.

You can check the definition file, search for the endpoints, and see what is their description of the `response` object. If it is missing, you may try adding a response object:

```
"responses": {
  "200": {
    "description": "Success",
    "content": {
      "application/json": {
        "schema": {
          "type": "array",
          "items": {
            "$ref": "#/components/schemas/Employee"
          }
        }
      }
    }
  }
}
```
"$ref": "#/components/schemas/Employee" should point to an entry within the components property:

```
components: {
schemas: {
Employee: {
type: "object",
properties: {
id: {
type: "string",
format: "uuid"
},
name: {
type: "string",
nullable: true
},
email: {
type: "string",
nullable: true
},
phone: {
type: "integer",
format: "int64"
}
},
additionalProperties: false
}
```

Please keep in mind that these are only examples and you need to check your OpenAPi definition file, and try to fix it.

If the issue is still reproducible, please send your source, so we could investigate this further.

Looking forward to hearing from you.

Sincerely,
Teodosia Hristodorova
Software Developer